Patient support apparatuses such as hospital beds, stretchers, cots, wheelchairs, and the like are employed to help facilitate care of patients in a health care setting. Conventional patient support apparatuses include a base operatively attached to a patient support surface upon which the patient is supported. Often, patient support apparatuses also include one or more movable members such as lift members, patient support deck sections, bed length extension members, bed width extension members, wheels, side rails, footboards, and headboards. Such movable members may be moved, manipulated, or otherwise positioned manually and/or with the use of one or more actuators. Typically, conventional patient support apparatuses employ linear actuators to move movable members. Conventional linear actuators are relatively large and tend to require an undesirable amount of space within the patient support apparatus. Rotary actuators may also be used to move the movable members. However, conventional rotary actuators are often unable to prevent movable members from back driving in response to force applied to the movable members, causing the movable members to move into undesirable positions in certain situations, such as during power loss or when components break. Additionally, conventional rotary actuators generally lack desirable stiffness which would otherwise give a caregiver or patient confidence in the structural integrity of the rotary actuator. Furthermore, conventional rotary actuators lack mechanisms that enable users to operatively disconnect an input member of the rotary actuator from an output member connected to the movable member so that the movable member can be easily and quickly moved, manipulated, or otherwise positioned manually, such as during a critical event (for example, when a patient is in cardiac arrest and requires CPR).
While actuators used in connection with patient support apparatuses have generally performed well for their intended purpose, there remains a need in the art for an actuator and patient support apparatus which overcome the disadvantages in the prior art.